MORB-derived amphibolites in the Paleozoic basement of the Aluminé Igneous-Metamorphic Complex, Neuquén, Argentina: Decoding its genesis, P-T evolution and pre-Andean regional correlations
DOI:
https://doi.org/10.1344/GeologicaActa2019.17.10Keywords:
MORB, Amphibolites, Thermobarometry, P-T path, Late Paleozoic, Triassic, Accretionary prismAbstract
Amphibolites included in the metapelitic sequence and as xenoliths in intrusive magmatic rocks outcropping in the southern sector of the Aluminé Igneous-Metamorphic Complex (AIMC), Neuquén, Argentina, are studied in detail in order to determine their origin and their subsequent metamorphic evolution. Field evidence and wholerock geochemistry indicate that these rocks were derived from a Mid-Ocean Ridge Basalt (MORB)-type protolith, and were accreted as tectonic slices into the metapelitic sequence that mainly formed the basal accretionary prism associated with a pre-Andean SW-NE subduction setting. Phase relationships, geochemistry of mineral assemblages and geothermobarometry indicate the presence of at least two metamorphic events (M1 1.9−3.9kbar, 677−745ºC and M2 6.4kbar, 723ºC) framed in a counterclockwise P-T path, comparable to those previously determined for the metapelitic country-rocks and metatroctolites outcropping in the same sector of the AIMC. Based on regional correlations and the agreement in the petrological, geochemical, geochronological and structural characteristics, we suggest that the MORB-derived Ñorquinco amphibolites and neighboring aluminous metasedimentary basement rocks of the AIMC belong to the eastern prolongation of the Western Series of the Coastal Accretionary Complex of Central Chile in west-central Argentina territory.
Downloads
Published
Issue
Section
License
Copyright (c) 2019 Geologica Acta
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Copyright
Geologica Acta is the property of the UB, GEO3BCN, IDAEA and UAB. Geologica Acta must be cited for any partial or full reproduction. Papers are distributed under the Attribution-Share Alike Creative Commons License. This license allows anyone to reproduce and disseminate the content of the journal and even make derivative works crediting authorship and provenance and distributing possible derivative works under the same or an equivalent license.
Author Rights
Authors retain the copyright on their papers and are authorized to post them on their own web pages or institutional repositories. The copyright was retained by the journal from the year 2003 until 2009. In all cases, the complete citation and a link to the Digital Object Identifier (DOI) of the article must be included.
The authors can use excerpts or reproduce illustrations of their papers in other works without prior permission from Geologica Acta provided the source of the paper including the complete citation is fully acknowledged.